Antioxidant CMK-5 mesoporous carbon covalently functionalized with gallic acid and ascorbic acid

Zare, Mahboobeh; Alinezhad, Heshmatollah

doi:10.22034/cjvs.2026.567496.1055

Antioxidant CMK-5 mesoporous carbon covalently functionalized with gallic acid and ascorbic acid

Document Type : Original Article

Authors

Mahboobeh Zare ¹

Heshmatollah Alinezhad ²

¹ Faculty of Medicinal Plants, Amol University of Special Modern Technologies, Amol, Iran.

² Department of Organic Chemistry, Faculty of Chemistry, University of Mazandaran, Babolsar, Iran.

10.22034/cjvs.2026.567496.1055

Abstract

Mesoporous carbon CMK-5 was synthesized and subsequently functionalized via covalent grafting with two potent natural antioxidants, ascorbic acid (AA) and gallic acid (GA), to develop novel antioxidant-active hybrid materials. The successful covalent attachment was confirmed through comprehensive characterization techniques, including fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). The antioxidant performance was systematically compared using two complementary assays: the DPPH radical scavenging assay and the ferric reducing antioxidant power (FRAP) test. The results indicated that functionalization effectively enhances the antioxidant activity of CMK-5. The DPPH scavenging capacity increased from less than 42.3% for pristine CMK-5 to 61.5% for CMK-5-AA, and 73.7% for CMK-5-GA. Similarly, in the FRAP assay, CMK-5-GA exhibited the highest reducing power. A consistent trend of CMK-5-GA > CMK-5-AA > CMK-5 was observed in both methods, unequivocally proving the superior efficacy of GA, attributed to its higher number of phenolic hydroxyl groups facilitating more efficient hydrogen atom transfer and electron donation. This work presented a suitable strategy for creating advanced antioxidant carbon-based hybrids for potential applications inbiomedicine, food preservation, or catalytic systems.

Keywords

Antioxidant

Ascorbic acid

CMK-5

Gallic acid

Subjects